Cluster of Sound Speed Fields by an Integral Measure
NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
Pagination or Media Count:
A technique to cluster large area oceanic predictions of sound speed into quasi-range independent areas is presented. Oceanic models produce high fidelity predictions of the oceanic sound speed fields that enable large-scale simulation of acoustic propagation with reasonable accuracy. Unfortunately, the oceanic models can produce sound speed fields quicker than can be digested by current technologies in underwater acoustic performance prediction systems. The speed bottleneck can be broken in two ways, a long term improvement in prediction technologies, and a interim process that allows similar acoustic areas to be aggregated into range dependent regions while maintaining a high degree of fidelity with the performance prediction resulting from using the complete oceanic model output. The interim process created must be capable of reflecting changes in sound speed field that control water born energy, and the changes in the field that effect the interaction with the oceanic bottom. This study uses vertically integrated gradient of the sound speed field as a basis for creating quasi-range dependent areas. The integrated gradient, when applied over a restricted latitudinal extent, gives an estimate of the mean ray curvature in the wave-guide. Since the field is integrated over depth, the effects of water depth are included in the calculation. The nature of the interaction with the oceanic bottom is not included in this calculation. The variations in bottom loss over the region of interest will be integrated into the analysis at a latter stage. The quantity cannot be used to predict transmission loss, but indicates where similar propagation conditions occur. The method is shown to be sensitive to the characteristics of the deep sound channel, and changes in the near surface structure of the sound speed field.
- Physical and Dynamic Oceanography
- Acoustic Detection and Detectors